Appendix D of the CPT manual lists all add-on codes.
download the addon. Should be on a zip file. Simply extract the file. place the folder with all the files in your >world of warcraft>interface>addons folder.
You need to have addon
You need to put the addon in to your addon folder. The easiest way to do this is download the curse client (free) and then anytime you want a new addon just install it via the "Install VIA Curse Client" button.
GET FIREFOX, (IF YOU DONT HAVE IT) DOWNLOAD THE ADDON ILLIMITUX AT https://addons.mozilla.org/en-US/firefox/addon/11037
the only jeapordy addon found is linked below to the Curse addon site. It adds some sounds for certain events.
You need to put the addon in to your addon folder. The easiest way to do this is download the curse client (free) and then anytime you want a new addon just install it via the "Install VIA Curse Client" button
Goto: http://wiki.garrysmod.com/?title=Add-On_Creation_%26_Folder_Structure#The_Info_File OR Read The Simple Tutorial Below: To create an addon for Garry's Mod, you need to place the relevent folders such as "lua", "settings", "maps", "materials" into a folder. The folder can be called anything, but a name that identifies the addon will help. You then need to create an addon information file. This can be done on any text editor but must be saved as "info.txt" and be placed in the root of the addon folder. The Layout Of The Text Inside The File Is As Follows: "AddonInfo" { "name" "<ADDON NAME>" "version" "<ADDON VERSION>" "author_name" "<ADDON AUTHOR'S NAME>" "author_url" "<ADDON AUTHOR'S WEBSITE>" "author_email" "<ADDON AUTHOR'S EMAIL ADDRESS>" "info" "<DETAILS OF THE ADDON>" "override" "<WHETHER THE ADDON WILL OVERRIDE ANOTHER ADDON OF THE SAME NAME, DELIMITED BY A "1" OR A "0".>" } NOTE: YOU DON'T NEED TO INLCUDE ALL OF THESE THINGS IN AN ADDON FILE. THE IMPORTANT ONES ARE: -NAME -VERSION The rest can be left out, but it's better to complete all of the lines you can. The "OVERRIDE" function can also be left out, because the default is 0. Below is an example of an addon folder structure: CAR MOD V6 (folder)¬ cfg (folder) data (folder) models (folder) lua (folder) materials (folder) info.txt (file) The "info.txt" file would look something like this: "AddonInfo" { "name" "Car Mod" "version" "6" "author_name" "carcreator68" "info" "THIS IS AN EXAMPLE FILE." } Ok Some Quick Rules TO Make Sure It Goes Well... 1) You MUST include the "AddonInfo" with capitals on the first line of the file. 2) You MUST include the { and } at the start and end of the info 3) The gaps between titles and values (e.g "name" and "Car Mod") can be as big or small, as long as they are at least one space. However, It helps to organize it like in the example above. The best way to do it is to use indents/tabs. 4) The Addon Folder (e.g Car Mod V6) must be placed in: %STEAM FOLDER%\steamapps\%STEAM USERNAME%\garrysmod\garrysmod\addons 5) If you want to check the addon has been included in Garry's Mod, (i.e if it doesn't appear to be working) go to the Garry's Mod Main Menu And Click "Extensions". Then, find the tab that says "Addons" and a list of all the loaded addons will be displayed. The addon will be shown with the name that you typed in the "name" category in the "info.txt" file. (e.g Car Mod) If you have followed the instructions correctly, and the mod itself works, it will be included in Garry's Mod. IMPORTANT NOTE: MANY OF THE MODS YOU CAN DOWNLOAD FOR GARRY'S MOD COME COMPLETE IN ADDON FOLDERS.
Yes, you can, however, not very many people would know about them. Most people tend to stick to the major addon sites that have tools that help addon authors. Sites like Curse and WoWInterface are better equipped to serve your addon to large audiences.
Download the playermodel addon from the workshop
A must have addon for all raiders in World of Warcraft is Deadly Boss Mods, also known as DBM. This addon will cause warnings to pop up on your screen when important things are going to happen. An example of this would be on the first boss in Heroic SFK. DBM will tell you to interrupt his self heals and will also warn you about when he about to transform towards the end of the fight.
Healbot is an addon, which means it is third-party software. It is most often downloaded from a game or addon site like Curse, WoWInterface or the like. If you are unsure, check if any of your online friends use addons, and where they get them. You can also google "healbot addon" and find the download results.
I would start by browsing the UI & Macros forum at the site in the related links. It is on the official wow forums and will give you a huge head-start in your addon development.